1. Field of the Invention
The present invention relates to a stencil printing machine for bringing an ink supply roller wherein ink is supplied onto its outer peripheral surface into contact with the inner peripheral surface of a printing drum and transferring the ink which has permeated through a stencil sheet to a sheet, thereby printing on the sheet, and relates in particular to an improvement in a structure for setting up a printing drum unit to the body of a printing machine, and a structure for supplying ink to an ink supply roller.
2. Description of the Related art
In a stencil printing machine, a printing drum on which a stencil sheet is wound around is set up to the body of a printing machine in the manner that the drum can be freely put on and taken off. In this way, the stencil printing machine is made to cope with the sort of printing color or maintenance. As shown in FIG. 1, an ink supply roller 3 is arranged inside a printing drum 1. The outer peripheral surface of the ink supply roller 3 is brought into contact with the inner peripheral surface of the printing drum 1. An ink amount control member (doctor rod) 5 is also arranged inside the printing drum 1 in the manner that the member 5 is located at a given interval from the outer peripheral surface of the ink supply roller 3 and in parallel to the roller 3. In this manner, a wedge-form ink pool 7 is made between the outer peripheral surface of the ink supply roller 3 and the outer peripheral surface of the ink amount control member 5 to be sandwiched therebetween.
An ink driving rod 9, which is in parallel to the ink supply roller 3, is rotatably arranged inside the ink pool 7. A non-illustrated gear fitted to one end of the ink driving rod 9 is engaged with a non-illustrated gear fitted to one end of the ink supply roller 3, so that the rod 9 can be rotated oppositely to the direction of the rotation of the ink supply roller 3 and in synchronization with the rotation thereof.
In operation of the stencil printing machine, the printing drum 1 is rotated in the direction of an arrow A, and the ink supply roller 3 is rotated in the direction of an arrow B. Thus, ink in the ink pool 7 revolves in a whirl around the ink driving rod 9 to produce an ink lump 11. The ink for producing the ink lump is supplied through an ink supply member (distributer) 13.
As shown in FIG. 2, conventionally, in the printing drum 1 having such a structure, its both ends in the axial direction of the drum 1 are rotatably supported by brackets 15. The brackets 15 at the two ends are connected with each other through support rods 17. These brackets 15, the support rods 17 and the printing drum constitute a printing drum unit 2.
A printing drum receiving section 19 is made in the body of the printing machine. A pressure drum 21 that can be freely rotated is arranged in the printing drum receiving section 19. A pair of parallel support rails 23 are fixed in the printing drum receiving section 19. The support rails 23 are positioned to have the same level above the pressure drum 21. In connection with the printing drum receiving section 19, openings are made, for example, in a side of the printing machine body and the two support rails 23 are slid and pulled out from the openings. The printing drum unit 2 is once held up and is then brought below the position between the support rails 23. In this way, the support rods 17 are hung on the support rails 23 so that the printing drum unit 2 can be fitted into the printing drum receiving section 19.
However, in the above-mentioned conventional stencil printing machine, a pair of the support rails in the printing drum receiving section is secured at the same level. Therefore, in order to fit the printing drum unit into the printing drum receiving section, it is unavoidable to hold up the printing drum unit once above the support rails and then bring down the unit, thereby hanging the support rods on the support rails. Thus, large power is necessary so that the printing drum unit cannot easily be fitted.
In the case of multicolor printing or color printing, as shown in FIG. 3, plural printing drums 2aand 2bmust be arranged above the central axis of a pressure drum 21 in a stencil printing machine. However, in the case that ink supply rollers 3 having the same structure are set up, the setting-up angles of the rollers 3 are caused to be different at the right and left printing drum units 2aand 2b. Therefore, in the one printing drum unit 2a, ink from a distributer 13 drops on the ink supply roller 3 to be supplied thereto. In the other printing drum unit 2b, however, there arises a problem that ink from a distributer 13 comes not to drop on the ink supply roller 3 so as to cause impossibility of supply of the ink. For this reason, in any stencil printing machine wherein plural printing drum units must be set up at different angles, it is difficult to make the printing drum units common.
In the light of the above-mentioned situations, the present invention has been made. An object thereof is to provide a stencil printing machine making it possible to set up a printing drum unit easily and further make the printing drum units, if any, common.
The stencil printing machine of a first aspect of the present invention comprises : a printing drum unit comprising a printing drum on which a stencil sheet is wound around, a pair of brackets which supports both ends of the printing drum so that the printing drum can be rotated, and at least one pair of support rods which is connected with the pair of the brackets and arranged in the same direction as the axial line of the printing drum; a printing drum receiving section having an opening, at a side position of a printing machine body, through which the printing drum unit can be put on and taken off, whereby the section can receive the printing drum unit; a first support rail which is disposed in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the first support rail supports the one support rod; and a second support rail which is disposed below the first support rail in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the second support rail supports the other support rod.
According to the stencil printing machine of the first aspect, the printing drum unit is moved from a side direction to the pulled-out first support rail so that the one support rod is supported. That is, unnecessary becomes the operation of holding up the printing drum unit once upwards and then bringing down the unit. Moreover, the one support rod is supported so that the printing drum unit is provisionally supported. Thus, this unit can be supported by one hand. In this state, the second support rail is pulled out and the other support rod is supported by the second support rail, so that the pair of the support rods is supported by the first and second support rails. In this way, setting-up of the printing drum unit is completed.
On the other hand, the stencil printing machine of a second aspect of the present invention comprises: a printing drum unit comprising a printing drum on which a stencil sheet is wound around, a pair of brackets which supports both ends of the printing drum so that the printing drum can be rotated, and at least one pair of support rods which is connected with the pair of the brackets and arranged in the same direction as the axial line of the printing drum; a printing drum receiving section having an opening, at a side position of a printing machine body, through which the printing drum unit can be put on and taken off, whereby the section can receive the printing drum unit; a first support rail which is disposed in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the first support rail supports the one support rod; a second support rail which is disposed below the first support rail in the printing drum receiving section and is freely pulled out in a horizontal direction from the opening, whereby the second support rail supports the other support rod; an ink supply roller which is disposed inside the printing drum and whose outer peripheral surface is brought in contact with the inner peripheral surface of the printing drum, whereby the ink supply roller is rotated; an ink supply member which is disposed inside the printing drum to jet out ink; and an ink guide roller which is positioned between the ink supply member and the ink supply roller to deliver the ink supplied from the ink supply member to the ink supply roller.
The stencil printing machine of the second aspect exhibits the same effect as the stencil printing machine of the first aspect. Moreover, the ink supplied from the ink supply member is delivered to the ink supply roller through the ink guide roller, so as to remove any restriction on the printing drum setting-up angle, which is essential for conventional ink supply structures in which ink is caused to drop freely. In this way, the direction along which the printing drum unit is set up becomes unrestricted so that, in any stencil printing machine having a plurality of the printing drum units, the printing drum units can be made common.
Other and further objects and features of the present invention will become obvious upon understanding of the illustrative embodiments about to be described in connection with the accompanying drawings or will be indicated in the appended claims, and various advantages not refereed to herein will occur to one skilled in the art upon employing of the invention in practice.